Although he was jumped outside the car, you asked what you would do if someone got in your car and threatened you?

Am not sure, but the first thing I do when I get in my car, even before my seat belt goes on, is lock the doors in my car. It can give you a small window of time to react if someone tries to open your door. They might not be expecting people to drive around with their doors locked.

According to the story, the carjacker was inside the car, with a gun to the kid's head. That's why he crashed the car, since he knew the guy didn't have a seat belt on.

I agree though, good thinking on the kid's part. It's a shame that he had to hit another occupied vehicle, instead of a stationary object like a light post, but the important thing is, he (and the people in the other car) made it out alive.